1. Field of the Invention
This invention relates to memory devices, and more particularly, to an embedded memory device and a method of performing a burn-in process on such an embedded memory device.
2. Description of Related Art
An embedded memory device is a type of memory device that integrates both the memory cells and the associated control logic circuit on the same integrated circuit (IC) chip. After an embedded memory device is completed in fabrication, it usually undergoes a burn-in process to test the reliability thereof.
Burn-in is the operation of a new IC product for a specified time under accelerated aging conditions prior to the shipment so as to sort out premature failures. The burn-in operation is an essential step for testing the reliability of the IC products. Conventionally, the burn-in process is performed after the IC chip is already packaged. During the burn-in process, all of the memory cells in the memory device are sequentially accessed to perform read/write operations to check if each memory cell can reliably hold data therein.
One conventional burn-in process is performed in such a manner that a plurality of IC memory devices are mounted together on a burn-in board, and then the burn-in board is placed in a burn-in oven to allow all the IC memory devices thereon to undergo the burn-in process simultaneously. Since a conventional burn-in board is limited in the number of pins and the layout area for power source, control circuits, address and data buses, the total number of IC memory devices that can be mounted together on the burn-in board for simultaneous burn-in test is limited. The throughput of the burn-in test is therefore low. Moreover, sharing the same data buses and power lines between a large number of IC memory devices on the burn-in board can cause delays to the test signals and insufficient power supply to the IC memory devices being tested.